Simvastatin preparations promote PDGF‐BB secretion to repair LPS‐induced endothelial injury through the PDGFRβ/PI3K/Akt/IQGAP1 signalling pathway

Endothelial barrier dysfunction is a critical pathophysiological process of sepsis. Impaired endothelial cell migration is one of the main reasons for endothelial dysfunction. Statins may have a protective effect on endothelial barrier function. However, the effect and mechanism of statins on lipopolysaccharide (LPS)‐induced endothelial barrier dysfunction remain unclear. Simvastatin (SV) was loaded in nanostructured lipid carriers to produce SV nanoparticles (SV‐NPs). Normal SV and SV‐NPs were used to treat human umbilical vein vascular endothelial cells (HUVECs) injured by LPS. Barrier function was evaluated by monitoring cell monolayer permeability and transendothelial electrical resistance, and cell migration ability was measured by a wound healing assay. LY294002 and imatinib were used to inhibit the activity of PI3K/Akt and platelet‐derived growth factor receptor (PDGFR) β. IQ‐GTPase‐activating protein 1 (IQGAP1) siRNA was used to knockdown endogenous IQGAP1, which was used to verify the role of the PDGFRβ/PI3K/Akt/IQGAP1 pathway in SV/SV‐NPs‐mediated barrier protection in HUVECs injured by LPS. The results show that SV/SV‐NPs promoted the migration and decreased the permeability of HUVECs treated with LPS, and the efficacy of the SV‐NPs exceeded that of SV significantly. LY294002, imatinib and IQGAP1 siRNA all suppressed the barrier protection of SV/SV‐NPs. SV/SV‐NPs promoted the secretion of platelet‐derived growth factor‐BB (PDGF‐BB) and activated the PDGFRβ/PI3K/Akt/IQGAP1 pathway. SV preparations restored endothelial barrier function by restoring endothelial cell migration, which is involved in the regulation of the PDGFRβ/PI3K/Akt/IQGAP1 pathway and PDGF‐BB secretion. As an appropriate formulation for restoring endothelial dysfunction, SV‐NPs may be more effective than SV.     

Effects of simvastatin treatment on oxidant/antioxidant state and ultrastructure of streptozotocin-diabetic rat lung

In the present study, we investigated the effects of simvastatin, a 3-hydroxy-3-methyl-glutaryl coenzyme A reductase inhibitor, on lipid metabolism, lipid peroxidation, antioxidant enzyme activities and ultrastructure of diabetic rat lung. Diabetes was induced by a single injection of streptozotocin (45 mg kg(-1), i.p.). After 8 weeks induction of diabetes, some control and diabetic rats were treated with simvastatin (10 mg kg(-1) rat day(-1); orally) for 4 weeks. Diabetes resulted in significantly high levels of blood glucose and plasma lipids. Malondialdehyde levels were unchanged after 12-week-old diabetic rats, whereas catalase activity significantly decreased in the lung. Glutathione peroxidase activity and nitric oxide level were significantly elevated in the diabetic lung. Histological analysis of the diabetic lung revealed some deterioration in the structure. Simvastatin treatment reduced plasma lipid levels and partially decreased the severity of hyperglycaemia. Catalase, glutathione peroxidase activities and nitric oxide levels were partially restored and accompanied by improved structure in diabetic lung by the simvastatin treatment. These results suggest that structural disturbances and alteration of antioxidative enzyme activities occurred in diabetic lung. Simvastatin treatment may provide some benefits in the maintenance of antioxidant status and structural organization of diabetes-induced injury of lung.     

血红素氧合酶-1/一氧化碳通路参与辛伐他汀抗高血压诱发的大鼠心肌肥厚

为了探讨他汀类药物抑制心肌肥厚的作用机制,本研究应用一氧化氮合酶抑制剂左旋硝基精氨酸[N-nitro-L-arginine, L-NNA,15 mg／(kg·d)]制备大鼠高血压心肌肥厚模型,并分别给予不同剂量辛伐他汀[5或30 mg／(kg·d)进行干预。6周后测大鼠左心室功能、左心室重量指数(left ventricular mass index,LVMI)、心肌脑钠素(brain natriuretic peptide,BNP)含量、心肌羟脯氨酸含量和心肌血红素氧合酶(heme oxygenase,HO)活性。在体外培养的新生大鼠心肌细胞中,观察辛伐他汀对血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)引起的心肌细胞肥大的抑制作用与细胞血红素氧合酶-1(HO-1)表达、HO活性及CO生成间的关系。结果表明,辛伐他汀干预明显减轻L-NNA处理大鼠的心肌肥厚(LVMI值、心肌BNP和羟脯氨酸含量均显著低于单纯L-NNA处理组),改善左心室舒张功能,而且心肌HO活性显著升高。在离体培养的原代乳鼠心肌细胞,辛伐他汀浓度依赖性地抑制Ang Ⅱ引起的细胞肥大(3H-亮氨酸掺入),并相应增加HO-1 mRNA表达、HO活性和CO生成量。应用HO抑制剂锌卟啉能有效抑制辛伐他汀抗Ang Ⅱ诱导的心肌肥大作用。结果提示:辛伐他汀上调HO-1／CO通路是其抗高血压诱发的心肌肥厚的机制之一。     

Diabetes reduces aortic endothelial gap junctions in ApoE-deficient mice: simvastatin exacerbates the reduction.

We examined the endothelial gap junctions in diabetic hyperlipidemic mice. Male apolipoprotein E (apoE)-deficient mice were made diabetic by streptozotocin. Three weeks later, the animals were treated with simvastatin for 2 weeks. The expression of aortic gap junctions in the non-diabetic (n=10), untreated diabetic (n=10), and simvastatin-treated diabetic animals (n=6) was analyzed. There was a >4-fold increase in serum cholesterol level and >50% increase in plaque areas in the diabetic mice, regardless of simvastatin treatment. Western blotting of aortae showed reduced expression of connexin37 (Cx37) and Cx40 in the diabetic mice, which were further decreased in the simvastatin-treated diabetic mice. Immunoconfocal microscopy showed that endothelial gap junctions made of Cx37 and Cx40 were both reduced in the untreated diabetic mice compared with the non-diabetic mice (decrease: Cx37, 41%; Cx40, 42%; both p<0.01). The reduction was greater in the simvastatin-treated mice (decrease in treated diabetic vs non-diabetic: Cx37, 61%; Cx40, 79%; both p<0.01; decrease in treated diabetic vs untreated diabetic: Cx37, 34%; Cx40, 63%; both p<0.01). Cx37 and Cx40 were decreased in the endothelium of plaque surface. Cx43 appeared in the medial layer and inner layer of the intima. All three connexins were rarely expressed in monocytes/macrophages inside the plaques. In conclusion, in apoE-deficient mice, streptozotocin-induced diabetes is associated with downregulation of endothelial Cx37 and Cx40 gap junctions. Short-term treatment with simvastatin exacerbates the downregulation.     

The cholesterol lowering properties of the complex compound simvastatin with glycyrrhizic acid (simvaglyzin) in experimental models

A molecular complex of simvastatin (SV) and glycyrrhizic acid (GA) (at their ratio of 1 : 4) has been synthesized. The complex named “simvaglyzin” (SVG) was stable in aqueous and aqueous-alcohol solutions at GA concentrations exceeding 0.2 mM. In vitro SVG acted as an uncompetitive inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA (3-HMG-CoA) reductase (Ki of 94 nM). Appearance of this inhibitory activity is associated with cytochrome P450-dependent conversion of SVG, because the addition of 1 mM metyrapone to the incubation medium fully prevented the inhibition of 3-HMG-CoA reductase. SV and SVG (used at 300 nM concentration) inhibited mevalonate synthesis rate by 39.15±8,27 and 38.85±3,04%, respectively. In vivo SVG showed a dose-dependent cholesterol lowering effect. In rats the cholesterol lowering effect of SVG used at daily doses equivalent to 66 and 100 mg/kg of SV was the same as the effect of SV administered at the daily dose of 200 mg/kg. The decrease in total cholesterol of blood serum was 7% and 9% (p < 0.05) and 8%, respectively. Myotoxicity of these SVG doses estimated by blood serum creatine phosphokinase (CPK) activity was lower than that of SV. In rats treated with SV the activity of CPK increased by 79% (p < 0.01), while in SVG treated rats it decreased by 30% and 36% (p < 0.05). Any increase of the hepatotoxicity markers alanine aminotransferase or aspartate aminotransferase in blood serum was not observed. The data suggest pharmacological synergism attributed to the SV-GA complex formation and increased safety of the resultant complex compared with a parent compound.     

辛伐他汀对糖尿病大鼠肾脏的保护作用及其可能机制

目的：观察辛伐他汀对糖尿病大鼠肾脏损伤的保护作用并探讨其可能的分子机制。方法：24只SD大鼠随机分为正常对照（NC,n=8）组和糖尿病造模组（n=16）。糖尿病造模组大鼠采用55 mg/kg链脲佐菌素（STZ）单次腹腔注射的方法建立糖尿病大鼠模型。造模成功后,糖尿病模型大鼠随机分为糖尿病（DM）组和糖尿病+辛伐他汀（DM+Sim）组。DM+Sim组大鼠每天给予辛伐他汀40 mg/kg灌胃,1次/日,连续4周。采用组织病理学方法观察肾脏的形态学改变和间质纤维化;采用分子生物学方法检测肾脏组织中内质网应激、炎性因子的表达以及细胞凋亡。结果：①与NC组相比,DM组可见肾小球和肾小管间质有明显的病理学改变,胶原纤维明显红染,呈不均匀分布;DM+Sim组形态学以及纤维化有明显改善。②DM组大鼠肾组织GRP78、p-IRE1α、NF-κB p65、MCP-1表达均高于NC组（P<0.05）,DM+Sim组GRP78、p-IRE1α、NF-κB p65、MCP-1表达较DM组均下降（P<0.05）。③TUNEL法检测,NC组肾小球及肾小管存在少量凋亡的细胞,DM组肾小球及肾小管存在大量凋亡的细胞（P<0.01）;与DM组比较,DM+Sim组凋亡的细胞明显减少（P<0.01）。结论：给予糖尿病大鼠辛伐他汀后,肾脏形态学以及纤维化明显改善,细胞凋亡明显减少。其对糖尿病肾脏的保护作用与抑制内质网应激和NF-κB炎症信号通路及减少肾脏细胞的凋亡有关。     

辛伐他汀对糖尿病大鼠阿司匹林抵抗的影响及其机制

目的：观察辛伐他汀对糖尿病大鼠阿司匹林抵抗的作用及机制。方法：选取雄性8周龄Wistar大鼠96只,随机分成糖尿病组和正常组（n=48）。糖尿病组大鼠腹腔一次性注射1%链脲佐菌素（STZ） （65 mg/kg,溶于0.l mmol/L、pH 4.5的柠檬酸缓冲液）来诱发糖尿病模型,正常组大鼠注射相同剂量的柠檬酸缓冲液。血糖大于16.8 mmol/L且同时具备多饮、多尿、体重减轻的糖尿病症状的大鼠认为糖尿病造模成功。糖尿病和正常大鼠分别随机分为糖尿病对照组（DM）、糖尿病阿司匹林组（DM-ASA）、糖尿病辛伐他汀组（DM-SIM）、糖尿病阿司匹林联合辛伐他汀组（DM-ASA+SIM）和正常对照组（NC）、正常阿司匹林组（NC-ASA）、正常辛伐他汀组（NC-SIM）、正常阿司匹林联合辛伐他汀组（NC-ASA+SIM）（n=12）。阿司匹林组、辛伐他汀组及阿司匹林联合辛伐他汀组分别给予10 mg/kg阿司匹林、2 mg/kg辛伐他汀、10 mg/kg阿司匹林加2 mg/kg辛伐他汀溶于PBS灌胃,对照组给予等量PBS灌胃。连续灌胃8周后,评价血小板聚集功能和血小板活化指标,检测大鼠血清一氧化氮（NO）、内皮素（ET）、前列环素（PGI2）、脂联素（APN）、血栓素B2（TXB2）水平和血清超氧化物歧化酶（SOD）、丙二醛（MDA）水平;进行大鼠胸主动脉离体血管张力实验评价内皮功能;检测大鼠胸主动脉血红素氧合酶-1（HO-1）、血红素氧合酶-2（HO-2）、内皮型NO合酶（eNOS）、磷酸化-内皮型NO合酶（p-eNOS）、抗凋亡蛋白（Bcl-2）、环加氧酶-2 （COX-2）等蛋白的表达水平。结果：与对照组大鼠相比,糖尿病大鼠其血小板活化及聚集值增高,且模型组呈现阿司匹林的反应性减低现象（P<0.05）;在糖尿病大鼠,阿司匹林联合辛伐他汀较单用阿司匹林组显著降低血小板活化及聚集值（P<0.05）,其通过上调HO-1、eNOS、p-eNOS、Bcl-2等蛋白的表达水平及升高血清APN水平,下调COX-2蛋白表达水平,通过改善内皮功能,调节TXA2/PGI2水平、增加NO水平,发挥其抗血小板作用。结论：糖尿病大鼠呈现阿司匹林反应性减低,辛伐他汀具有潜在的改善血小板对阿司匹林的反应性的作用。